A broadcasting channel (BCH) is used for transmitting system information in a communication system such as a cellular system. A terminal detects parameters of a cell by demodulating BCH information when accessing the communication system. Accordingly, a base station should transmit the BCH without any information on the channel information of the terminal, which means that the base station cannot use a link adaptation technique such as a power control or frequency selective scheduling. In addition, since the terminal does not know a bandwidth of a system that the terminal wants to access before demodulating the BCH, the BCH is transmitted through a minimum bandwidth among a plurality of system bandwidths. Accordingly, the terminal occasionally demodulates the BCH under deteriorated conditions.
In spite of the deteriorated demodulation conditions, the BCH should be designed in such a way that is can be demodulated in a low signal-to-interference noise ratio (SINR) because the BCH includes essential information for operation of the terminal. This means that a channel coding rate on the BCH must be very low.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.